Millions of people around the world are suffering from HIV/AIDS, and millions more are likely to become infected each year. Many medications are currently available for the treatment of HIV/AIDS including HIV protease inhibitors (PI's), nucleoside/nucleotide reverse transcriptase inhibitors (NRTI's) and non-nucleoside reverse transcriptase inhibitors (NNRTI's). Most current treatment regimens require a combination of at least three medications, most commonly two NRTI's and either a PI or a NNRTI.
PI's are poorly soluble and are very difficult to formulate. Originally, PI's were provided as liquid formulations in which the PI component was dissolved. Currently, the most widely used PI dosage forms are gelatin capsules containing a fill solution in which the active ingredient is dissolved. The fill solutions required to dissolve the PI often contain excipients that cause discomfort or irritate the gastrointestinal system. Furthermore, only a limited amount of the PI can be dissolved in these dosage forms which therefore limits the amount of the PI loaded in each gelatin capsule.
In order to obtain the necessary dose of an individual PI, a patient must take several gelatin capsules at any given dosing period, which is repeated several times in a day. As mentioned above, therapy for HIV patients includes multiple medications that commonly includes a PI. Moreover, these patients often times require additional medications such as antibiotics and lipid lowering agents to control opportunistic infections and other diseases or conditions they may be afflicted with. Consequently, these patients can take an extraordinary number of medications in a variety of different dosage forms over the course of a given day.
Such treatment regimens are further complicated by the fact that some of the dosage forms (including some PI's) require refrigerated storage conditions to prevent degradation of the active ingredients. For subjects residing in economically challenged or developing countries where refrigerators are not as common in households, such storage conditions represent a particularly challenging dilemma.
It has also been observed that upon administration of a PI from gelatin capsules there is variability in the blood levels of the active ingredient from subject to subject and even within the same subject. That is, some patients receiving treatment can have very high or very low blood levels of the PI. In turn, this can lead to unwanted adverse events in those patients experiencing high blood levels of the drug or rendering the treatment less effective or ineffective in those patients experiencing low blood levels of the drug.
In order to increase the bioavailability of PI's it is recommended that patients take the gelatin capsule formulation following a meal to increase the overall bioavailability of the active ingredient. Bioavailability can further vary depending on fat content in each meal. Unfortunately, many patients do not always adhere to this routine due to the complexity of their treatment regimens or otherwise. Often patients will take the medication on an empty stomach that leads to low bioavailability of the drug, and perhaps ineffective treatment.
Therefore, it is desirable to have a PI dosage form that reduces or eliminates gastrointestinal adverse events. It is also desirable to have such a dosage form that can be loaded with more active ingredient to reduce the pill burden on patients. Furthermore, it is desirable to have a dosage form that provides little variability in the blood levels of the PI within a subject and throughout a patient population. Another desirable feature would be a dosage form that provides similar blood levels of a PI regardless of whether or not a patient takes the medication following a meal. Yet another desirable feature would be a dosage form that does not have to be refrigerated to prevent degradation of the PI.